In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/D...In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).展开更多
We investigate a wavelength-division-multiplexing passive optical network(WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying(DP...We investigate a wavelength-division-multiplexing passive optical network(WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying(DPSK) downstream signals and on-off keying(OOK) upstream signals,respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier(RSOA) as an intensity modulator at the optical network unit(ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio(ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate(BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.展开更多
In frequency division duplex(FDD)massive multiple-input multiple-output(MIMO)systems,a bidirectional positional attention network(BPANet)was proposed to address the high computational complexity and low accuracy of ex...In frequency division duplex(FDD)massive multiple-input multiple-output(MIMO)systems,a bidirectional positional attention network(BPANet)was proposed to address the high computational complexity and low accuracy of existing deep learning-based channel state information(CSI)feedback methods.Specifically,a bidirectional position attention module(BPAM)was designed in the BPANet to improve the network performance.The BPAM captures the distribution characteristics of the CSI matrix by integrating channel and spatial dimension information,thereby enhancing the feature representation of the CSI matrix.Furthermore,channel attention is decomposed into two one-dimensional(1D)feature encoding processes effectively reducing computational costs.Simulation results demonstrate that,compared with the existing representative method complex input lightweight neural network(CLNet),BPANet reduces computational complexity by an average of 19.4%and improves accuracy by an average of 7.1%.Additionally,it performs better in terms of running time delay and cosine similarity.展开更多
In this study,a novel dual permanent magnet excited vernier machine(DPMEVM)with magnets shifting in stator is proposed.Compared with the conventional permanent magnet synchronous machine(PMSM),the DPMEVM based on the ...In this study,a novel dual permanent magnet excited vernier machine(DPMEVM)with magnets shifting in stator is proposed.Compared with the conventional permanent magnet synchronous machine(PMSM),the DPMEVM based on the bidirectional field modulation effect can operate in a wider torque range.However,the torque ripple of a conventional DPMEVM is high because of the superposition of the torque generated by the stator-side and rotor-side PMs.Consequently,a novel DPMEVM with magnets shifting is proposed to further reduce the torque ripple.First,the topologies and working principles of the baseline machine and proposed machines are introduced.Second,the torque-contribution harmonics are analyzed and calculated using the Maxwell tensor method.The calculation results reveal that the DPMEVM,benefiting from multiple working harmonics,can offer an enhanced torque capability compared to the PMSM.In addition,the torque ripple characteristics of the proposed machines are analyzed.It is verified that the torque ripple can be significantly reduced through magnets shifting.Third,the performances of the baseline machine and proposed machines are analyzed and compared in terms of flux density,open-circuit back-EMF,and torque characteristics.In addition,the proposed principle can be extended to machines with the same unit motor.Finally,a 120s-110p prototype machine is manufactured for validation.展开更多
基金supported by the Erciyes University Scientific Research Projects Coordination Unit (No.FDK-2019-8750)。
文摘In this paper, we have evaluated a bidirectional wavelength division multiplexing passive optical network(WDM-PON) employing intensity modulated/direct detection optical orthogonal frequency division multiplexing(IM/DD-OFDM). The proposed system employs 100 Gbit/s 16 quadrature amplitude modulation(16-QAM) downstream and 5 Gbit/s on-off keying(OOK) upstream wavelengths, respectively. The proposed system is considered low-cost as non-coherent IM/DD OFDM technology and a simple reflective semiconductor optical amplifier(RSOA) colorless transmitter are employed and no dispersion compensating fiber(DCF) is needed. Based on the bit error rate(BER) results of WDM signals, the proposed WDM-PON system can achieve up to 1.6 Tbit/s(100 Gbit/s/λ × 16 wavelengths) downstream transmission over a 30 km single mode fiber(SMF).
基金the Alexander von Humboldt Foundation for their support
文摘We investigate a wavelength-division-multiplexing passive optical network(WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying(DPSK) downstream signals and on-off keying(OOK) upstream signals,respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier(RSOA) as an intensity modulator at the optical network unit(ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio(ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate(BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.
基金supported by the National Natural Science Foundation of China(12005108)the Shandong Provincial Natural Science Foundation Youth Project(ZR2020QF016)the National Natural Science Foundation of China(U2006222)。
文摘In frequency division duplex(FDD)massive multiple-input multiple-output(MIMO)systems,a bidirectional positional attention network(BPANet)was proposed to address the high computational complexity and low accuracy of existing deep learning-based channel state information(CSI)feedback methods.Specifically,a bidirectional position attention module(BPAM)was designed in the BPANet to improve the network performance.The BPAM captures the distribution characteristics of the CSI matrix by integrating channel and spatial dimension information,thereby enhancing the feature representation of the CSI matrix.Furthermore,channel attention is decomposed into two one-dimensional(1D)feature encoding processes effectively reducing computational costs.Simulation results demonstrate that,compared with the existing representative method complex input lightweight neural network(CLNet),BPANet reduces computational complexity by an average of 19.4%and improves accuracy by an average of 7.1%.Additionally,it performs better in terms of running time delay and cosine similarity.
基金Supported by the National Natural Science Foundation of China under Grant 52025073the Natural Science Foundation of Jiangsu Province under Grant BK20210770.
文摘In this study,a novel dual permanent magnet excited vernier machine(DPMEVM)with magnets shifting in stator is proposed.Compared with the conventional permanent magnet synchronous machine(PMSM),the DPMEVM based on the bidirectional field modulation effect can operate in a wider torque range.However,the torque ripple of a conventional DPMEVM is high because of the superposition of the torque generated by the stator-side and rotor-side PMs.Consequently,a novel DPMEVM with magnets shifting is proposed to further reduce the torque ripple.First,the topologies and working principles of the baseline machine and proposed machines are introduced.Second,the torque-contribution harmonics are analyzed and calculated using the Maxwell tensor method.The calculation results reveal that the DPMEVM,benefiting from multiple working harmonics,can offer an enhanced torque capability compared to the PMSM.In addition,the torque ripple characteristics of the proposed machines are analyzed.It is verified that the torque ripple can be significantly reduced through magnets shifting.Third,the performances of the baseline machine and proposed machines are analyzed and compared in terms of flux density,open-circuit back-EMF,and torque characteristics.In addition,the proposed principle can be extended to machines with the same unit motor.Finally,a 120s-110p prototype machine is manufactured for validation.
